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This program estimates the parameters of birth weight for your frequency distribution. There are two components of any birth weight distribution, with a total of three parameters. The main (predominant) distribution is Gaussian, and is defined by a mean and a standard deviation. The second (residual) distribution is a more irregular portion lying outside the lower tail of the predominant distribution. The residual distribution is summarized here as a percent of the whole population. This program also provides estimates of the exact frequency distributions for each component of your birth weight distribution. For a fuller discussion of these parameters and their biological interpretation, see the Frequency Distribution of birth weight. Instructions Enter your birth weight data in 2 steps. Use step 1 (below) to select program options. Step 2 on the next page allows you to enter birth data. Your data are saved online for one hour. This allows you to experiment with different values and review the tutorial sections of this site without having to re-enter your values. To erase saved data, exit your browser or click here. Step 1 of 2 Provide a title for your output, and then select the size of your weight categories (100g, 250g etc.). You must also define your category boundaries by entering the lower boundary of your lightest and your heaviest weight categories. For example, if your weight categories go from '500-999g' through '5000-5499g', then you would enter 500 as the 'Low End Boundary' and 5000 as the 'High End Boundary'. See an example of how to fill in these fields.
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NIEHS
Epidemiology Branch
Contact Dr. Wilcox | Last update November 22, 2000
